Individual Calling Line Identification (ICLID) is a telephone on-hook capability that provides a called party with information about the caller before the incoming call is answered. Information can include the date and time of the call and caller telephone extension number. A data message, preceded by a channel seizure signal, is sent in conjunction with the ringing signal from the central office to the called party during the silent interval after the first 20-Hz, 2-second ringing phase.
ICLID service is designed for use with the voice portion of existing loop connections. The digitally formatted message is transmitted through a stream of data bits of standardized digital format. The message is sent once, without retransmission capability. The channel seizure signal, sent at the beginning of each message to alert the called party equipment of the coming information through physical connection of an appropriate interface, is typically composed of thirty continuous bytes of octal 125 (i.e., 01010101), or 250 milliseconds of a 600-Hz square wave. Transmission of data follows thereafter and is completed prior to the next 20-Hz ringing signal. For a detailed description of the method and apparatus for sending the data message, reference is made to U.S. Pat. No. 4,551,581 issued to Doughty on Nov. 5, 1985.
The ICLID "special service" feature has conventionally been used to display the message information, sent during the silent interval between the first two rings, at a dedicated alpha-numeric display at a selected subscriber station. The display may be of the LED or LCD variety. The called party can view the actual ICLID data on display before answering the telephone and the display can remain until cleared. The details of such usage are described in U.S. Pat. No. 4,582,956 issued to Doughty on Apr. 15, 1986.
The prior art limited use of reproducing ICLID information on a called party's local display has not reached full development of the capabilities of the ICLID service. While incoming information is processed and held for display, this operation is only a temporary function which is interrupted by the next incoming call or when cleared. There is no meaningful permanent storage of the ICLID information. While the existing systems may provide temporary storage of incoming ICLID information for later recall and redial by the subscriber who has been away from the telephone, a relatively small number of incoming calls will exceed the limited memory capability provided.
The ICLID information service in the prior art has not been implemented to provide the user with other relevant information concerning the calling party. Conventionally, only the limited ICLID information itself is displayed. With the now commonplace integration of the personal computer in the telephone environment, an interactive exchange between the ICLID service and related information available through the computer would overcome a shortcoming of the prior art ICLID service. For example, in a business setting, there is often the need for the called party to instantly recall previously stored related information about the calling party upon receipt of the telephone call.